A German multicenter trial found CAAS vessel fractional flow reserve (vFFR) met its planned noninferiority test against pressure-wire fractional flow reserve (FFR), an approach that could avoid wire placement and hyperemic drugs during invasive coronary procedures.
The American College of Cardiology (ACC) reported that major adverse cardiac events (MACE) occurred within one year in 3% of patients whose revascularization was guided by vFFR and 4.1% of those treated using FFR. ACC put the risk difference at −1.01 percentage points. The upper bound of the one-sided 97.5% confidence interval was 1.29 percentage points, below the trial’s prespecified absolute margin of 3.5 percentage points.
The result differed under a post-hoc primary sensitivity analysis using a relative margin of 1.44, which did not establish noninferiority, ACC reported. A separate post-hoc per-protocol sensitivity analysis using that margin did meet the test. ACC said the study authors linked the relative analysis result to fewer events than expected, which made the margin less stringent in practice than they had intended.
The trial protocol says investigators lowered planned enrollment from 1,926 to 1,054 after a blinded sample-size recalculation. The calculation used a pooled 12-month event rate of 4.2% among 933 participants with follow-up through December 2023. The protocol says the recalculation was not prespecified.
ACC reported that 1,053 patients were randomized at eight German hospitals. Participants had acute or chronic coronary syndromes and at least one intermediate coronary narrowing; their median age was 69. The trial’s one-year MACE measure included cardiac death, nonfatal heart attack or unplanned revascularization prompted by clinical need.
CAAS vFFR estimates vessel FFR using angiographic images, a three-dimensional vessel reconstruction and measured aortic-root pressure, according to the protocol. Pressure-wire FFR uses a wire and a hyperemic agent such as adenosine. Both methods are used during invasive coronary angiography. The protocol says vFFR can avoid wire placement and hyperemic agents, while wire-based assessment can add time and effort.
The findings were presented at TCT 2026 on Nov. 2 and published the same day in the Journal of the American College of Cardiology. The protocol describes the study as investigator-initiated, reports no external funding and says participating centers received CAAS workstations free of charge. It plans MACE follow-up at two and five years but gives no dates for those results.
